The manufacturing of a semiconductor product typically involves a number of processing steps, or jobs, carried out on one or more pieces of processing equipment or tools. For example, the manufacture of electronic devices in a wafer fabrication facility involves the performance of processing steps such as film deposition, photolithography, etching, heat treatment, and dopant introduction with respect to a wafer substrate such as silicon. For each job, wafers must be delivered to the load port of the tool being employed, and, when multiple tools are required, the wafers must be transferred there between. Likewise, when tools are employed for measuring properties of semiconductor wafers, the wafers must be delivered to the tools.
Silicon wafer lots are generally provided to tools in carriers, such as front opening unified pods, or FOUPs. A FOUP may hold 25 wafers in a secure and safe controlled environment. Another type of carrier is a single/dual wafer transport carrier/pod, or SOUP. A FOUP, SOUP, or other type of carrier allows the wafers to be removed for processing or measurement by the tools and robotic handling systems.
Current operational scenarios in the semiconductor industry require that the FOUP (or other wafer carrier) be part of the job setup sequence. In typical scenarios, wafers to be processed or measured have been loaded in carriers prior to the job set up. However, in some cases, wafers are stored in a bare wafer stocker (BWS), or other single wafer management system, and a carrier for delivery of wafers to various job sites may not yet be identified. The latter scenario poses a challenge to perform job setup, deliver and start control jobs. Conventionally, if the wafers are stored in a BWS, the transfer of the wafers into the FOUP is not part of the automated process.
In the scenario in which the delivery FOUP or carrier is known at the outset, it is possible that the wafers have not yet been placed in the carrier at the start of the job preparation. As reservation linking the job to the tool conventionally cannot take place until the wafers are placed in the carrier, the automation process is hindered.
A need therefore exists for an improved automated wafer preparation process.